Position an oven rack in the middle and heat to 325°F. Line an 8-inch square pan with parchment.
Melt butter in a saucepan over medium-low heat, then remove from heat.
Stir in sugar, cocoa powder, vanilla, and salt while the butter is still hot.
Let cool until warm, not hot (5–10 min). <
Id=”instruction-step-5″>5. Add cold eggs one at a time, stirring well after each. <
Id=”instruction-step-6″>6. Stir in flour until thick and smooth. <
Id=”instruction-step-7″>7. Fold in optional nuts or chocolate chips. <
Id=”instruction-step-8″>8. Spread batter evenly in pan. Smooth out. <
Id=”instruction-step-9″>9. Bake 20–30 minutes until edges are dry and center is slightly underdone.
D=”instruction-step-10″>10. Cool completely before slicing. Chill for clean cuts.
